golang/go

x/net/nettest: TestTestConn runs out of memory on Plan 9

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#20,489 opened on May 24, 2017

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NeedsFixOS-Plan9help wanted

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Description

CL 37404 added TestTestConn, which is running out of memory on Plan 9.

runtime: out of memory: cannot allocate 323485696-byte block (1029013504 in use)
fatal error: out of memory

runtime stack:
runtime.throw(0x11b06c, 0xd)
	/tmp/workdir/go/src/runtime/panic.go:596 +0x7b
runtime.largeAlloc(0x13478000, 0x100, 0x3)
	/tmp/workdir/go/src/runtime/malloc.go:816 +0xdf
runtime.mallocgc.func1()
	/tmp/workdir/go/src/runtime/malloc.go:709 +0x38
runtime.systemstack(0x103ee000)
	/tmp/workdir/go/src/runtime/asm_386.s:393 +0x5c
runtime.mstart()
	/tmp/workdir/go/src/runtime/proc.go:1116

goroutine 30390 [running]:
runtime.systemstack_switch()
	/tmp/workdir/go/src/runtime/asm_386.s:347 fp=0x103f4ddc sp=0x103f4dd8
runtime.mallocgc(0x13478000, 0x0, 0x0, 0xb)
	/tmp/workdir/go/src/runtime/malloc.go:708 +0x670 fp=0x103f4e30 sp=0x103f4ddc
runtime.growslice(0xfe140, 0x50b02000, 0xf6c6000, 0xf6c6000, 0xf6c6060, 0x212ac000, 0x4d, 0x50)
	/tmp/workdir/go/src/runtime/slice.go:140 +0x1bb fp=0x103f4e70 sp=0x103f4e30
testing.(*common).log(0x1044e240, 0x17d9e0a0, 0x4d)
	/tmp/workdir/go/src/testing/testing.go:551 +0x11f fp=0x103f4ea8 sp=0x103f4e70
testing.(*common).Errorf(0x1044e240, 0x11d4e9, 0x19, 0x103f4f18, 0x1, 0x1)
	/tmp/workdir/go/src/testing/testing.go:575 +0x5c fp=0x103f4ec8 sp=0x103f4ea8
vendor/golang_org/x/net/nettest.resyncConn(0x1044e240, 0x1a93a0, 0x107da4f8)
	/tmp/workdir/go/src/vendor/golang_org/x/net/nettest/conntest.go:435 +0x158 fp=0x103f4f24 sp=0x103f4ec8
vendor/golang_org/x/net/nettest.testConcurrentMethods(0x1044e240, 0x1a93a0, 0x107da4f8, 0x1a93a0, 0x107da520)
	/tmp/workdir/go/src/vendor/golang_org/x/net/nettest/conntest.go:382 +0x245 fp=0x103f4f58 sp=0x103f4f24
vendor/golang_org/x/net/nettest.timeoutWrapper(0x1044e240, 0x103ea328, 0x121b70)
	/tmp/workdir/go/src/vendor/golang_org/x/net/nettest/conntest.go:56 +0x1ab fp=0x103f4fac sp=0x103f4f58
vendor/golang_org/x/net/nettest.testConn.func11(0x1044e240)
	/tmp/workdir/go/src/vendor/golang_org/x/net/nettest/conntest_go17.go:23 +0x31 fp=0x103f4fbc sp=0x103f4fac
testing.tRunner(0x1044e240, 0x107da450)
	/tmp/workdir/go/src/testing/testing.go:747 +0xa5 fp=0x103f4fe8 sp=0x103f4fbc
runtime.goexit()
	/tmp/workdir/go/src/runtime/asm_386.s:1635 +0x1 fp=0x103f4fec sp=0x103f4fe8
created by testing.(*T).Run
	/tmp/workdir/go/src/testing/testing.go:789 +0x250

goroutine 1 [chan receive]:
testing.(*T).Run(0x1044e000, 0x11acd8, 0xc, 0x121b2c, 0x998d1)
	/tmp/workdir/go/src/testing/testing.go:790 +0x267
testing.runTests.func1(0x1044e000)
	/tmp/workdir/go/src/testing/testing.go:1004 +0x50
testing.tRunner(0x1044e000, 0x10411eec)
	/tmp/workdir/go/src/testing/testing.go:747 +0xa5
testing.runTests(0x103e8070, 0x1b8120, 0x1, 0x1, 0x0)
	/tmp/workdir/go/src/testing/testing.go:1002 +0x23f
testing.(*M).Run(0x1045bf98, 0x10414070)
	/tmp/workdir/go/src/testing/testing.go:921 +0xcc
main.main()
	vendor/golang_org/x/net/nettest/_test/_testmain.go:44 +0xc5

goroutine 6 [chan receive]:
testing.(*T).Run(0x1044e090, 0x1197f1, 0x3, 0x103ea308, 0x5134be)
	/tmp/workdir/go/src/testing/testing.go:790 +0x267
vendor/golang_org/x/net/nettest.TestTestConn(0x1044e090)
	/tmp/workdir/go/src/vendor/golang_org/x/net/nettest/conntest_test.go:76 +0xef
testing.tRunner(0x1044e090, 0x121b2c)
	/tmp/workdir/go/src/testing/testing.go:747 +0xa5
created by testing.(*T).Run
	/tmp/workdir/go/src/testing/testing.go:789 +0x250

goroutine 7 [chan receive]:
testing.(*T).Run(0x1044e1b0, 0x11b943, 0x11, 0x107da450, 0x303da101)
	/tmp/workdir/go/src/testing/testing.go:790 +0x267
vendor/golang_org/x/net/nettest.testConn(0x1044e1b0, 0x103ea328)
	/tmp/workdir/go/src/vendor/golang_org/x/net/nettest/conntest_go17.go:23 +0x3c6
vendor/golang_org/x/net/nettest.TestConn(0x1044e1b0, 0x103ea328)
	/tmp/workdir/go/src/vendor/golang_org/x/net/nettest/conntest.go:37 +0x28
vendor/golang_org/x/net/nettest.TestTestConn.func1(0x1044e1b0)
	/tmp/workdir/go/src/vendor/golang_org/x/net/nettest/conntest_test.go:123 +0x82
testing.tRunner(0x1044e1b0, 0x103ea308)
	/tmp/workdir/go/src/testing/testing.go:747 +0xa5
created by testing.(*T).Run
	/tmp/workdir/go/src/testing/testing.go:789 +0x250

goroutine 30393 [chan receive]:
internal/poll.(*asyncIO).Wait(...)
	/tmp/workdir/go/src/internal/poll/fd_io_plan9.go:84
internal/poll.(*FD).Read(0x10430460, 0x107db210, 0x10607c00, 0x400, 0x400, 0x0, 0x0, 0x0)
	/tmp/workdir/go/src/internal/poll/fd_plan9.go:73 +0x106
net.(*netFD).Read(0x10430460, 0x10607c00, 0x400, 0x400, 0x400, 0x0, 0x0)
	/tmp/workdir/go/src/net/fd_plan9.go:85 +0xb2
net.(*conn).Read(0x107da520, 0x10607c00, 0x400, 0x400, 0x0, 0x0, 0x0)
	/tmp/workdir/go/src/net/net.go:176 +0x55
go.(*struct { io.Reader }).Read(0x107da558, 0x10607c00, 0x400, 0x400, 0x400, 0x0, 0x0)
	<autogenerated>:1 +0x44
io.copyBuffer(0x1a7aa0, 0x107da550, 0x1a7a80, 0x107da558, 0x10607c00, 0x400, 0x400, 0x109affc4, 0x107da558, 0x107da558, ...)
	/tmp/workdir/go/src/io/io.go:390 +0xd8
io.CopyBuffer(0x1a7aa0, 0x107da550, 0x1a7a80, 0x107da558, 0x10607c00, 0x400, 0x400, 0x0, 0x103d4c40, 0x103d4c40, ...)
	/tmp/workdir/go/src/io/io.go:371 +0x5c
vendor/golang_org/x/net/nettest.chunkedCopy(0x1a7880, 0x107da520, 0x3043e0f0, 0x107da520, 0x103f4f60, 0x8)
	/tmp/workdir/go/src/vendor/golang_org/x/net/nettest/conntest.go:449 +0xe6
created by vendor/golang_org/x/net/nettest.testConcurrentMethods
	/tmp/workdir/go/src/vendor/golang_org/x/net/nettest/conntest.go:344 +0x9a

goroutine 31115 [syscall, locked to thread]:
syscall.Syscall6(0x8, 0x10607c00, 0x400, 0xffffffff, 0xffffffff, 0x0, 0x0, 0x1, 0x1, 0x0, ...)
	/tmp/workdir/go/src/syscall/asm_plan9_386.s:54 +0x5
syscall.Pread(0x8, 0x10607c00, 0x400, 0x400, 0xffffffff, 0xffffffff, 0x103ee000, 0x55239, 0x549d8)
	/tmp/workdir/go/src/syscall/zsyscall_plan9_386.go:218 +0x5c
syscall.Read(0x8, 0x10607c00, 0x400, 0x400, 0x0, 0x0, 0x0)
	/tmp/workdir/go/src/syscall/syscall_plan9.go:124 +0x48
os.fixCount(...)
	/tmp/workdir/go/src/os/file_plan9.go:249
os.(*File).read(0x107da508, 0x10607c00, 0x400, 0x400, 0x0, 0x14c3, 0x0)
	/tmp/workdir/go/src/os/file_plan9.go:249 +0x3c
os.(*File).Read(0x107da508, 0x10607c00, 0x400, 0x400, 0xffffffff, 0x0, 0x0)
	/tmp/workdir/go/src/os/file.go:103 +0x5d
os.(*File).Read-fm(0x10607c00, 0x400, 0x400, 0x400, 0x0, 0x0)
	/tmp/workdir/go/src/net/fd_plan9.go:85 +0x37
internal/poll.newAsyncIO.func1(0x107de3e0, 0x107db210, 0x10607c00, 0x400, 0x400)
	/tmp/workdir/go/src/internal/poll/fd_io_plan9.go:54 +0xc0
created by internal/poll.newAsyncIO
	/tmp/workdir/go/src/internal/poll/fd_io_plan9.go:43 +0xaf

goroutine 31112 [chan send]:
vendor/golang_org/x/net/nettest.resyncConn.func1(0x1a93a0, 0x107da4f8, 0x107e0880)
	/tmp/workdir/go/src/vendor/golang_org/x/net/nettest/conntest.go:426 +0x79
created by vendor/golang_org/x/net/nettest.resyncConn
	/tmp/workdir/go/src/vendor/golang_org/x/net/nettest/conntest.go:424 +0x8f
FAIL	vendor/golang_org/x/net/nettest	25.967s

See https://build.golang.org/log/91d479d449f2d4e18ff585e87fcf0867a4fd2ea7

Contributor guide

Research direction
Investigate memory allocation in resyncConn and chunkedCopy functions in conntest.go. Look for goroutine leaks or unbounded buffering that could cause OOM on Plan 9.
Tech stack
go
Domain
backend
Issue type
Bug
DifficultyEstimated implementation difficulty for a new contributor, from 1 for very small changes to 5 for expert-level work.
2
Estimated timeA rough time range for an experienced contributor to investigate, implement, test, and prepare a pull request.
1-3 hours
Activity statusHow available the issue appears right now: fresh, active, stale, blocked, or waiting on maintainer input.
Active
ClarityHow clearly the issue explains the expected change, acceptance criteria, and next step.
Clear
Prerequisites
Go
Newbie friendlinessA 1-100 score estimating how approachable this issue is for first-time contributors.
40